I have an irrigation system with an underground well, a tank, a pump start relay switch, a timer and a pressure switch set to turn on at 20 psi and off at 50 psi.

There are 3 zone valves connected to the timer. There is a separate zone for hose bibs that is not connected to a valve or the timer, as I want the bibs to supply water any time on demand.

Both the timer and the pressure switch are connected to the pump start relay.

The problem is probably in the wiring and I could use some help:

When the timer turns the pump on to water any of the 3 zones, the pressure switch (connected to the relay) shuts off the pump after a few minutes (when the tank reaches 50 psi).

The pressure switch doesn't turn on the pump when it gets below 20 psi (it is a new switch), so there is never water on demand at the hose bibs.

The pump is first controlled by the timer, which allows the pressure switch to deliver water only when the timer is "ON".

If you connect the timer to only operate the zone valves, and allow the pressure switch to operate the pump independently, then your problem should be solved.

Hope this helps, get back if you have any other questions.

You really need to look at the pump control schematic. In many of my designs I use a timer to disable the pump if it is running or valves are left open for too long. Thus, preventing the well from being ran dry. That is the only reason I can think of the timer being connected to the start relay.

The pump is enabled by the pressure switch and timer. The pressure switch has been replaced.

Here's what's wrong:
1) the pressure switch is installed or set improperly or
2) the timer has failed.

I have had a similar problem - my system has 12 zones and then another 3 that I run on alternate days. During the recent long hot summers, the well has occasionally run low to dry - and I have had to let it sit idle for a few days to build back up. Fortunately, we have city water for the house and use the well only for irrigation and rare emergencies. Should I tie a timer into the pump start relay to reduce the likelihood of running dry? What's the best way to do that - what specific things will I need?

You need a timer/counter (120V) a pump start relay and valve positioners and manual reset/start and stop buttons. The pump start relay is energized from the pressure switch (which probably energizes the pump right now).

The timer is set longer than the valve switching and the operation of the valves resets the timer. This is how water flow is determined. If the timer times out, then no water valve is switching and the system is off. Both the timer and counter are reset if the timer times out. The manual reset button not only resets the counter and the timer but it also restarts the system.

If valve switching is every 10minutes and a count of 10 is showing, then the system has been in operation for 100minutes. Simply have the counter interrupt power to the pump start relay after a certain interval (if you want the system to stop after 2 hours, set the counter to 12).